360 magnum into abody and efi/carby questions

Yes it was very unfortunate I couldn't figure it out. I spent thousand's of dollars over 2 years until I just couldn't spend any more. I am hoping it was just something in my block and the next magnum I buy is ok. I am a bit nervous as it cost me so much.

What is the 380 short block Abodybomber mentioned?
Also for mid 300s HP will the factory throttle body be ok or will it be too small cfm
cheers